Iran cast the strike as a response to last week's Islamic State attacks in Tehran, which killed at least 18 people and wounded more than 50.

The Bahraini cleric wrote religious justifications for the enslavement of thousands of women from Iraq's Yazidi minority and helped establish the IS branch in Libya.

A joint working group of the three guarantor states has held three sessions, two in Ankara and one in Oslo, to specify technical and geographical details of four safe zones in Syria, he added.

As reported yesterday, Russian Federation suspended cooperation under the "Memorandum on the Prevention of Incidents and Ensuring Air Safety in Syria" on Monday after the USA shot down a Syrian Army fighter jet.

"This is the same location where another pro-regime UAV dropped munitions near Coalition forces before it was shot down, June 8", the US military says.

A defense official says the drone was approaching a military camp near the Syria-Jordan border.

The drone shoot down comes amid heightened tensions in Syria following the shoot down on Sunday of a Syrian fighter jet that had dropped bombs on local forces backed by the U.S.in the fight against ISIS.

"In accordance with rules of engagement and in collective self-defence of coalition-partnered forces, [the Syrian jet] was immediately shot down by a US F/A-18E Super Hornet", a coalition statement read.

"There has been neither a Security Council decision, nor a request from the official authorities of the Syrian Arab Republic as a sovereign state", Russia's Interfax news reported.

The Pentagon insisted it was not seeking to escalate the conflict and had acted only after the Syrian jet in question had dropped bombs near United States partner forces involved in the fight to wrest Raqqa from Isis control.

The Syrian government has said that the U.S. move "reveals with no doubt the truth about the USA support of terrorism", according to state media.

The push by Syrian government forces in the Daraa area appears headed for the Jordanian border, two weeks after Assad's troops reached the border with Iraq for the first time in years.

"The situation is back as it was in Daraa city and fighting is ongoing", said Daraa-based opposition activist Ahmad al-Masalmeh. He is blaming the government for the truce's collapse.

The news comes amid growing tensions between the US and Russian Federation, with the Western military alliance North Atlantic Treaty Organisation having begun a new military exercise near Russia's borders in the Baltic region. It is still unclear what the missiles struck, and Iran has provided few details.

That incident followed two others involving U.S. fire against pro-regime forces on the ground as they came close to the garrison.

Sharif says the missile launch reflects Iran's "military power" though Iran has no intention of starting another war.

According to a report by the Syrian Center for Policy Research, the conflict has claimed the lives of over 470,000 people, injured 1.9 million others, and displaced almost half of the country's pre-war population of about 23 million within or beyond its borders.

Washington also described those strikes as self-defense.

"It is absolutely illegal", Russia's Deputy Foreign Minister Mikhail Bogdanov said Tuesday of the presence of American forces in Syria.

Most of the Australian strikes have been in Iraq, though its aircraft do also operate over Syria.

The top United States general, Joseph Dunford, sought to play down the repercussions of the incident, insisting the hotline established eight months ago between U.S. central command in Qatar and its Russian equivalent in Syria was still open and functioning.

A Russian jet came within five feet of a US reconnaissance plane near the Baltic Sea Tuesday after the military announced earlier that day it had shot down an aircraft belonging to the Moscow-backed Syrian government.